Hyperthyroidism

Definition

Hyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often referred to as an "overactive thyroid."

Alternative Names

Overactive thyroid

Causes, incidence, and risk factors

The thyroid gland is an important organ of the endocrine system. It is located in the front of the neck just below the voice box. The gland produces the hormones thyroxine (T4) and triiodothyronine (T3), which control the way every cell in the body uses energy. This process is called metabolism.

Hyperthyroidism occurs when the thyroid releases too much of its hormones over a short (acute) or long (chronic) period of time. Many diseases and conditions can cause this problem, including:

Treatment

Treatment depends on the cause and the severity of symptoms. Hyperthyroidism is usually treated with one or more of the following:

Antithyroid medications

Radioactive iodine (which destroys the thyroid gland and stops the excess production of hormones)

Surgery to remove the thyroid

If the thyroid must be removed with surgery or destroyed with radiation, you must take thyroid hormone replacement pills for the rest of your life.

Beta-blockers such as propranolol are used to treat some of the symptoms, including rapid heart rate, sweating, and anxiety until the hyperthyroidism can be controlled.

Expectations (prognosis)

Hyperthyroidism is generally treatable and only rarely is life threatening. Some of its causes may go away without treatment.

Hyperthyroidism caused by Graves disease usually gets worse over time. It has many complications, some of which are severe and affect quality of life.

Complications

Thyroid crisis (storm), also called thyrotoxicosis, is a sudden worsening of hyperthyroidism symptoms that may occur with infection or stress. Fever, decreased mental alertness, and abdominal pain may occur. Immediate hospitalization is needed.